Explanation:

- Prakash's initial salary was Rs75,000.

- He receives a salary increment of 8%.

- To calculate the increment, multiply his current salary by 8%: Rs75,000 x 0.08 = Rs6,000.

- Add the increment to the original salary: Rs75,000 + Rs6,000 = Rs81,000.

- Option 1: Rs81,000 - This option correctly represents the new salary after the increment.

- Option 2: Rs80,000 - This does not include the full increment amount.

- Option 3: Rs1,08,000 - This is an incorrect calculation, much higher than the actual new salary.

- Option 4: Rs77,000 - This is lower than the original salary, so it cannot be correct.